Area Forecast Discussion
Issued by NWS Indianapolis, IN

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FXUS63 KIND 270638

Area Forecast Discussion
National Weather Service Indianapolis IN
238 AM EDT WED JUL 27 2016

The LONG TERM Section has been updated below.


Issued at 323 PM EDT Tue Jul 26 2016

A broad frontal zone will remain in place across the Ohio Valley
much of this week, with several subtle waves and a warm moist
airmass in place providing several opportunities for showers and
storms, particularly across the southern half of central Indiana.
Thunderstorm chances will persist throughout the seven day
forecast period as this active pattern remains.


.NEAR TERM /Rest of Tonight/...
Issued at 951 PM EDT Tue Jul 26 2016

Most of the convection has dissipated across the far southern
forecast area, and some weakening convection continues across
southern Illinois.

Overall the forecast is in good shape. Made some minor tweaks to
PoPs, ending chances just south of I-70 and adjusting the far south
to match current trends. For the most part convection is weakening
thanks to loss of instability, and this can be seen on radar as well
as warming cloud tops on satellite.

Cannot rule out additional isolated convection in the southern two-
tiers or so of counties tonight thanks to lingering boundaries and
weak convergence, so left slight chance PoPs there overnight.
Although high clouds will remain across southern areas tonight, feel
that they will thin enough for areas of fog to form, mainly where
rain has fallen today. Also, dewpoints have come up in the western
forecast area, so added patchy fog there.

Made minor tweaks to min temperatures.

Previous discussion follows...

Storms associated with an earlier weak wave have exited the area,
although additional storms, largely diurnally driven, have
developed along the frontal zone just south and southwest of the
area. Cannot rule out these making it into the southern portion of
the area tonight, and will have to maintain some pops. Will be
closely monitoring hydro threat, particularly across the southeast
where some flash flooding occurred earlier. Storms have been
highly efficient precipitation producers in a pseudotropical
airmass with deep warm cloud depth. This is unlikely to change in
the coming days.

Fog may be an issue tonight but will depend significantly on how
much cloud cover or possible thunderstorms are across the area.
Will leave these details to the evening shift to monitor.

Consensus temperatures appear reasonable based on low level
thermal progs and were generally accepted. With only slight
changes in the airmass expect a similar gradient to last night
across the area.


.SHORT TERM /Wednesday through Friday/...
Issued at 323 PM EDT Tue Jul 26 2016

Will require pops every period throughout the short term as the
frontal zone remains in or near the area and one or more subtle
upper level waves interacts with it. Hydrologic issues could
easily develop later this week as rain chances will be highest
across the south which received ample rainfall today, particularly
across the southeast where 5 plus inches may have fallen in some
spots. Airmass quality will remain highly precipitation efficient,
but uncertainty in timing and organization of storms precludes
flood watch products at this time.

Consensus temperatures again appear reasonable throughout but will
be significantly dependent on convective influences, which would
lower max temps. This may be particularly apparent on Thursday
when pops are highest.


.LONG TERM /Saturday through Tuesday/...

Issued at 238 AM EDT Wed Jul 27 2016

ECMWF suggests a lingering frontal boundary will be found across
the southern parts of Central Indiana on Saturday while a broad
weak trough lies aloft. Confidence remains low for a precip
event...however given these features have included pops through
Sunday as they pass. This is what superblend suggests.

On Monday and Tuesday...ridging aloft and High pressure across
Central Indiana is suggested by the ECMWF...however superblend
continue to carry pops. Given the expected subsidence beneath a
ridge and large...broad high pressure in place across the eastern
United States...have trended pops dry. Temps look to remain near
seasonal normals.


.AVIATION /Discussion for the 28/0600Z TAF Issuance/...

Issued at 1155 PM EDT Tue Jul 26 2016

High pressure is along the southern Great Lakes area resulting in
calm/light winds. VFR conditions are the rule for now, but will be
monitoring for areas of fog developing toward sunrise. Latest
guidance has improved visibilities for KBMG and KHUF and this may be
due to the amount of cirrus that is streaming northeast from what is
left of convection that was over the middle Mississippi/lower Ohio
Valley region.  MVFR for conditions then for after 09Z with the
possibility of brief IFR conditions at KBMG and KHUF.


.IND Watches/Warnings/Advisories...


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